Originally Posted by
tempocyclist
I have programmed the top "hidden hood" buttons to shift the rear derailleur in either direction, but in all honestly I rarely use them. I should get the wireless module so I can flip Garmin pages.
My time trial bike is in "full syncro" mode, so the buttons only shift up or down the gear range, the front derailleur is completely controlled by the Di2 brain.
Totally worth the small cost. You'll also get a Di2 battery level readout on your Garmin, as well as a gear position indicator. The latter is surprisingly useful if you live in a hilly area: when you're on a really steep climb, a glance at the computer will indicate whether you still have a bailout gear available.